40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  40m Log  Not logged in ELOG logo
Entry  Mon Oct 22 20:44:49 2012, Ayaka, Update, Adaptive Filtering, microphone noise mic_noise2.png
    Reply  Tue Oct 23 00:51:41 2012, Jamie, Update, Adaptive Filtering, microphone noise 
       Reply  Tue Oct 23 10:24:42 2012, Ayaka, Update, Adaptive Filtering, microphone noise 
Message ID: 7589     Entry time: Mon Oct 22 20:44:49 2012     Reply to this: 7592
Author: Ayaka 
Type: Update 
Category: Adaptive Filtering 
Subject: microphone noise 

I will do some experiments on acoustic noise canceling during my stay.
Now I am planning to cancel acoustic noise from PMC and see how the acoustic noise work and how we should place microphones.

First, I measured the noise in microphones and its circuit.
-blue, green, red, solid lines; microphone signals
-blue, green, red, dashed lines; un-coherent noise in signals
-yellow, black, solid lines; circuit noise (signal input is open, not connected to the microphones)

We can see the acoustic signal above 1 Hz, and the circuit does not seem to limit its sensitivity. But I do not know why yellow and black is so different. I will check it tomorrow.

ELOG V3.1.3-